The present invention relates to a method for the manufacture of a weather strip for motor vehicles. In particular, the invention concerns a method for the manufacture of a weather strip including a profiled section with a cross-section in the form of a web terminating in an enlarged head, the extent of the web of the profiled section being variable between a minimum value and a maximum value in a predetermined manner along the length of the weather strip.
FIG. 1 illustrates in perspective a piece of weather strip of the type specified above, comprising a substantially channel-shaped anchoring section 1, for example of hard elastomeric material, and a sealing section, for example of spongy elastomeric material, indicated 2. As shown in the drawing, the cross-section of the sealing section is essentially in the form of a web 2a terminating in an enlarged end or head portion 2b. Such a weather strip can be used, for example, as the air-tight member and aesthetic connecting member between the front pillars and upper cross member of a front door of a motor vehicle and the corresponding edge of the motor vehicle body, as illustrated in FIGS. 2 and 3. FIG. 2 illustrates schematically a motor vehicle A provided with front doors P of the so-called "wrap-over" type, that is, the type in which the upper edge of the door is located above the gutter and joins substantially with the roof R of the motor vehicle, as seen in FIG. 3. A weather strip of the type illustrated in FIG. 1 is conveniently located in the interspace between the upper edge p.sub.2 of the door P and the corresponding edge r of the roof R of the motor vehicle; at a certain distance from the upper edge r of the roof R a rib N is formed by pressing of the sheet metal forming the roof and the anchoring section 1 of the weather strip is snap-engaged onto it. The head or enlarged portion 2b of the weather strip closes the interspace between the door and the roof with an air-tight seal. The weather strip is conveniently mounted along the edge of the body intended to face the front pillar p.sub.1 of the door and the upper edge p.sub.2, as shown in FIG. 2. The air-tightness is especially important, particularly in correspondence with the pillar p.sub.1, since air penetrating the interspace between the door and the body during forward movement of the vehicle would tend to cause considerable aerodynamic noise.
In practice, it is not always possible to form the engagement rib N at the same distance from the edge r of the roof R. Consequently, with the use of a weather strip of the type shown in FIG. 1, that is with a web 2a of constant height, some zones of the weather strip will be slightly sunken while other zones will be slightly raised when the weather strip is in use.
These disadvantages could be overcome if it were possible to make, in a simple, precise, rapid and cheap manner, a weather strip of the type shown in FIG. 4, that is, a weather strip whose sealing section can have a web 2a with a height which differs locally in correspondence with variations in the distance between the rib N and the edge r of the body.
Clearly, a weather strip of this type may be made by moulding. However, this solution is extremely expensive, particularly when it is wished to make weather strips with two parts formed from materials of different hardnesses.